CO-22 Denial Code: Care May Be Covered by Another Payer
When a patient has more than one coverage, payers follow COB rules to decide who pays first. If a payer's records show other coverage that it considers primary, or if its COB record is out of date, it denies with CARC 22 until it receives the primary payer's adjudication or an updated COB record.
Also appears as OA-22 and PR-22. The group code changes who is responsible, not the reason.
CARC 22 means the payer believes another insurance plan should pay first under coordination of benefits (COB). Confirm the patient's coverage order, bill the correct primary payer, and have the patient update COB with the plan if its records are wrong.
Common causes of CO-22.
- Patient has another active plan that is primary (employer plan, spouse's plan, Medicare)
- Payer's COB record is outdated and still lists terminated coverage
- Dependent coverage order under the birthday rule was applied differently than expected
- Auto, workers' compensation, or liability coverage may apply
- Patient has not returned the payer's annual COB questionnaire
How to work a CO-22 denial.
The order matters: confirm the facts before deciding between a corrected claim, a reconsideration, or an adjustment.
- 1Verify all active coverage with the patient and run eligibility with both payers.
- 2If another plan is primary, bill it first, then send the secondary claim with the primary's payment information.
- 3If the payer's COB record is wrong, ask the patient to update it with the plan. Many plans will only accept this from the member.
- 4Resubmit once the COB record is corrected, and track the claim against timely filing.
How to keep CO-22 from coming back.
- Ask about all coverage at every intake and at least annually
- Review other-coverage information returned in eligibility responses
- Flag patients with recent Medicare eligibility or job changes
Fixing this at the source usually sits with eligibility verification →
Questions about CO-22.
Denials that often travel with this one.
CO-109: Claim Not Covered by This Payer
CO-109 means the claim was sent to the wrong payer or contractor. How to identify the correct payer, including carve-outs and Medicare Advantage, and rebill.
Read about CO-109 →CO-27: Expenses Incurred After Coverage Terminated
CO-27 (often PR-27) means coverage was not active on the date of service. How to verify eligibility, find new coverage, and bill correctly before timely filing.
Read about CO-27 →CO-31: Patient Cannot Be Identified as Insured
CO-31 means the payer cannot match the patient to a member on its files. How to fix member ID, name, and date of birth mismatches and resubmit the claim.
Read about CO-31 →Add a Dedicated Denial Specialist
RCM Staff places trained denial management specialists inside your EHR and clearinghouse to work the queue, correct and appeal claims, and track root causes by payer.
Kevin Jamito has 18+ years of U.S. healthcare revenue cycle management experience across billing, coding, practice management, and offshore RCM operations. He founded RCM Staff to give U.S. healthcare teams dedicated Philippines-based specialists who work inside their existing systems.